The present invention relates to an electrical component sequencing and taping machine. More particularly, the present invention relates to a machine for preparing programmed packages of taped components for use in printed circuit board component insertion machines.
It has become the practice in forming printed circuit boards to employ machines to automatically insert components into the boards in desired positions. Two types of automatic insertion machines now in use include those which are supplied by a plurality of separate magazines and taped component sources, the machine being programmed to select and remove desired components from each of the sources, and those of the other type which are supplied with a single pre-programmed component tape or single magazine source. The latter type of insertion machine, and in particular that which employs a single tape, is preferred because of its relatively simple construction and because the taped components are held under positive control thereby permitting high-speed component insertion.
Machines to prepare sequenced component belts from a plurality of separate belts of individual axial leaded components have been developed to meet a growing need for sequenced belts as disclosed in U.S. Pat. No. 3,421,284, issued Jan. 14, 1969, the property of the assignee of this patent. That machine uses a mechanical memory apparatus to control the release of stored components from a plurality of dispensers. The components fall into preselected positions on a moving conveyor which continuously transports sequenced components to a taping mechanism. Taping retains the components in sequence on flexible belts for storage prior to use in a circuit board component insertion machine. More advanced machines now employ electronic circuitry to control the dispensation of components onto the moving conveyor, however the operating principles illuatrated in U.S. Pat. No. 3,421,284 are still applicable and that patent should be considered as incorporated herein by reference. U.S. Pat. No. 3,669,309 also discloses a machine for dispensing components from separate storage units onto a moving conveyor in a selected sequenced order.
While the performance of these machines has been technically satisfactory, the burgeoning demand for belts of sequenced components has led to efforts to accelerate machine output by increasing the speed of the moving conveyor belt past the dispensers. These efforts have been substantially unsuccessful because of the increased momentum of the conveyor elements which contact the component leads. At the original conveyor design speed, the leads of the descending axial leaded components fall into and are retained for transport in uniformly spaced notches along the edges of the conveyor. However, when in order to increase output rate the conveyor speed is substantially increased, the component leads on contact with the fast-moving conveyor, fail to seat in the notches and the component is frequently thrown from the conveyor. This causes work stoppages, potential machine damage and lost efficiency.
What is needed is an improved component sequencing and taping machine which can receive components on the moving conveyor and deliver said components to the taping mechanism at a higher rate while maintaining a complete and properly sequenced arrangement of components.
In the improved machine of this invention the conveyor speed is reduced while the rate of dispensing components is disproportionately increased resulting in closer spacing of components on the conveyor and a higher rate of component delivery to the taping mechanism. The lower linear velocity of the conveyor, and redesigned and newly spaced notches on the conveyor assure retention thereon of the deposited components in proper sequence. Accordingly, the difficulties associated with a higher speed conveyor are avoided while output is increased. In the slower unimproved machine the pitch distance between components on the conveyor equalled the spacing distance between component dispensers. In the improved machine the component pitch distance is reduced to a submultiple of the dispenser spacing distance such that an integral number, e.g., 1, 2, 3, 4, of components are added between the components as they would have been deposited by the unimproved machine.